At first I thought Seekport also suffers the 301 redirection bug that Google once did, replacing the real URLs with redirects pointing to is. But no, it’s not Seekport – Feedburner is redirecting the users using a status 302 moved temporarily:

I think that’s wrong. The item is not only temporarily available under the URL http://ideengeberin.de/blog/artikel-129.html, it will stay there permanently. So Feedburner should use a „301 Moved Permanently“ to not harm its users in search engines.